ID? GM 3963647 Rec. port intake, aluminum?

[George W.]

Application? Thanks, g.

[Clem Z.]

Re: ID? GM 3963647 Rec. port intake, aluminum?

please recheck the casting number as it does not compute

[George W.]

Re: ID? GM 3963647 Rec. port intake, aluminum?

I won't be able to check it until the '65 962/208 long block I have purchased arrives next week. This intake was included with the deal, and that's the number I was given. Thanks, G.

[Joe L.]

Re: ID? GM 3963647 Rec. port intake, aluminum?

George-----

I believe that the GM #3963647 was the intake manifold intended for the "still-born" 1970 Corvette LS-7. While the engine was never installed in any PRODUCTION Chevrolet vehicle, some SERVICE engines were built and the manifold was also available under GM PART #3977610. It was discontinued from SERVICE in July, 1970.

[George W.]

Re: ID? GM 3963647 Rec. port intake, aluminum?

Joe, cool! Thanks. I guess it's only value is as a functioning BB sq. port? G.

[Joe L.]

Re: ID? GM 3963647 Rec. port intake, aluminum?

George-----

Well, it would be priceless for a person that has a rare 1970 LS-7 Corvette and needs a manifold. Otherwise, it's just a functional rectangular port, high rise big block manifold.

I would be interested in getting some pictures of it when you get it, if possible.

[George W.]

Re: ID? GM 3963647 Rec. port intake, aluminum?

Joe, I will send you photos when I get it (early next week). Thanks again, G.

[Clem Z.]

joe i was under the impression my new 1970

454 450 HP chevelle came with the "sunken" manifold,where the carb flange was lower than the intake ports because this engine was to be used in a corvette and it needed the lower manifold for the aircleaner to clear the corvette hood. this is the same as the 68 and 69 3X2 corvette manifold vs the 67 3X2 manifold. i replaced the manifold with a hi rise the day i brought the car home and stll have the orignal manifold someplace

[Warren F.]

Re: joe i was under the impression my new 1970

Your assumption is correct Clem, that's what happened.

Fortunately for the Chevelle crowd, they are able to just swap a L78/L72 intake on and go on their merry way!

[Joe L.]

Re: joe i was under the impression my new 1970

clem-----

Yes, all LS-6 used the GM #3963569 manifold. This is the low rise, "pancake" manifold. This manifold was also used on all 1970-71 L-78 in Chevelles and Camaros. The LS-7, had there been any built, would have used the high rise manifold of GM casting #3963647. I believe that this manifold was similar to the 3933163. The latter is probably what you installed on the Chevelle.

I don't know why that GM used the "pancake" manifold in the Chevelle and Camaro applications. As far as I know, this manifold was designed for the Corvette application in order for fitment under a stock, big block style hood. It was not necessary, at all, for Chevelles and I believe that Camaros could also have used the high rise style, too, with no fitment problem. However, as it turned out, no big blocks after 1969 received a high rise manifold. At least, no PRODUCTION big blocks did.

[George W.]

I love how a "wierd" piece gets our attention

"The hunt is the fun"! I learned the truism of this as a young game shooter. Learning the habits of the game, and putting oneself in position to "score" is much more rewarding than the "kill". Ok, it's late, and I've had a a cocktail or two, but I'm trying to convey how the energy of the hunt is more rewarding than the acquisiton of the prize. Later, G.

[George W.]

Re: ID? GM 3963647 Rec. port intake, aluminum?

Joe, please send your e address so I can send you the photos. G.

[Joe L.]

Re: ID? GM 3963647 Rec. port intake, aluminum?

George-----

Sent.

[George W.]

Re: ID? GM 3963647 Rec. port intake, aluminum?

Joe, did you get the photos? G.

[Joe L.]

Re: ID? GM 3963647 Rec. port intake, aluminum?

George-----

Yes, I did. I found them to be quite interesting and informative. Now, I'm really questioning whether or not the GM casting #3963647 manifold that I THOUGHT was the casting number used for the GM PART #3977610 was really ever used for that. Now, I don't really think so.

The manifold pictured is a high rise aluminum GM manifold. However, it has a carb flange for a SPREAD BORE carburetor (e.g. Q-Jet, etc.). Also, this manifold does not have any provisions for a choke, at all. Strangely, though, it does have provisions for exhaust cross-over. I don't understand what purpose this serves with no choke. However, it may be that it simply heats the carburetor base for improved fuel atomization.

The LS-7 was scheduled to have a Holley square flange carb. It was also scheduled to have a divorced-style choke. Neither of these accomodations are present on this manifold. So, I don't see how it could have been the 3977610.

There's one other feature of this manifold that may be the "tip-off" as to its original use. Note that the heater hose boss is not drilled and tapped. That pretty much excludes the possibility that this manifold was intended for use on ANY passenger car, either for PRODUCTION or high performance SERVICE use (i.e. an early GM-supplied performance manifold sold over-the-counter only). That really only leaves one possibility: a marine application. For that application, all of the "pieces fit". This was very likely a special marine manifold supplied to Mercury Marine or other boat engine manufacturers with the engine assemblies supplied to them for further conversion to marine application.

Other than the possible use of this manifold on the LS-7, which now seems VERY unlikely, I can't think of any other PRODUCTION application that this manifold could have served. It's definitely from the 1969-70 period. At least, it would have been originally released then. For how long it might have been manufactured, I don't know.

Usually, pieces like this that are used for marine applications only are not available through GM SERVICE parts channels. So, the finished part number of this manifold, whether it be the same as the casting number or some other number, would never appear in any GM parts catalog of any description. Instead, the manifold would have been supplied as part of engine assemblies shipped to the marine engine converter and, very likely, available in SERVICE as a seperate part through the marine engine manufacturer ONLY.